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HomeMy WebLinkAboutCC - Storm Drainage Calcs ESE CONSULTANT S ESE Consultants, Inc. 3103 W. Sheryl Drive ENGINEERING - PLANNING - SURVEYING - ENVIRONMENTAL Meridian,Idaho 83642 TEL: 208-424-0020 STORMWATER MANAGEMENT REPORT FOR DAYSPRING SUBDIVISION NO. 1 rmONAL ENS 9461370 D [7 O X•9�of 1DP� 4 � i l2 j' o Anna Leigh Hirning _••� ° I Professional Engineer 7z -- .q - �J A J; t3 , Idaho License No.9461370 q ra } — ; i 13 o �r s� ±rooau'iiconna� January 2026 LOCATED IN: CITY OF MERIDIAN ADA COUNTY, IDAHO TABLE OF CONTENTS SUBJECT SECTION Project Overview 1 Stormwater Management Design 2 Stormwater Equations 3 Primary Conveyance & Stormwater Facility Calculations 4 Intensity-Duration-Frequency Curve 5 Pipe Flow Calculations 6 Drainage Basin Map 7 SECTION 1 - Project Overview Dayspring Subdivision No.1 is a part of a multi-phase mixed use development located in the City of Meridian,Ada County, Idaho.The development is situated along the south side of West Ustick Road, between North Black Cat Road and North McDermott Road. The applicant proposes to develop eighteen (18) single family residential lots and twenty (20) multifamily lots with this phase of the project. The development includes the construction of homes and infrastructure to include roads, sidewalks, a stormwater management facility, utilities, and other improvements typical of residential construction. There are also fourteen (14) commercial lots located within the northern portion of Dayspring Subdivision Phase 1 that are being platted with this phase but are anticipated to be developed in the future. Existing Conditions The project site is currently bound by a single-family residential development to the east(Tricia's Crossing Subdivision) and vacant agricultural land to the west and south. The project site itself is comprised of existing irrigated farmland with several abandoned houses and ancillary buildings, and irrigation delivery ditches. The existing terrain is relatively flat with slopes generally less than one percent. The site slopes down gradient from north to south. Geotechnical Characteristics A Geotechnical Engineering Report was prepared by ALLWEST for the Dayspring Subdivision (f.k.a. Porter Complex Development), dated September 2, 2020. The soils were generally described as surficial lean clay with sand or sandy lean clays with thickness of 1 to 3 feet, overlaying varying layers and mixtures of native silty and sandy soils. Underlying the silty and sandy soils, were generally observed poorly graded gravels with silt and sand to test pit depths of up to 13' bgs. Groundwater Groundwater was observed by ALLWEST during testing in June of 2020 at depths ranging from 7.5' -13.5' bgs. Additional groundwater monitoring performed by Geotek commenced in August 2024 and is ongoing. There are currently 30 active piezometers onsite, and groundwater is observed at depths ranging from 3.2'-12.3' bgs.Geotek's results are summarized in the attached report dated December 2025. Soil Infiltration ALLWEST performed soil infiltration tests at 8 (eight) locations within the project site which resulted in rates ranging from a low of 0.25 in/hr to a high of greater than 20 in/hr.An infiltration rate of 1 in/hr was utilized for design purposes. SECTION 2 - Stormwater Management Design Design Criteria The Stormwater Management Plan described herein has been designed according to the Ada County Highway District Policy Manual. The proposed Stormwater Management Design has been prepared to meet the following requirements and guidelines: ♦ The Rational Method (Q=CiA) has been utilized to calculate peak flows. Runoff coefficients were used per the ACHD Policy Manual. Rainfall intensities were determined using the ACHD adopted Intensity-Duration-Frequency Curve located in Section 5 of this report. Calculations for the requisite time of concentration (Tc) value are enclosed. The overland flow and gutter flow segments of the Tc were calculated based on the equations provided in the ACHD Policy Manual and enclosed within this report for reference. ♦ Pipe flow calculations are provided to demonstrate that the primary stormwater conveyance system is sized to adequately handle stormwater flows based on the 100-yr storm event. ♦ The residential lots in this phase will be alley-loaded and grading has been designed to direct stormwater to either an alley or local road to be collected by the stormwater system. The front yard area has been accounted for in stormwater calculations to be conservative, however it is anticipated that yard drains will be installed during home construction during final landscaping to facilitate infiltration of front yard drainage. ♦ Stormwater generated within Commercial Lots 12 & 13, Block 3 has been accounted for in calculations due to their location internal to the subdivision improvements. Commercial Lots 2-13, Block 2 have not been included in stormwater calculations. It is anticipated that the commercial lots north of W McMurtrey St. will be designed to retain stormwater generated onsite at the time of future development. ♦ High groundwater observed through the site necessitated the use of Vertical Sand Filters and bioretention swales for the storage and infiltration of the 100-year storm event. An infiltration rate of 1 inch per hour has been used for the design of the vertical sand filters and swales. Sand and grease traps are provided for pretreatment for the vertical sand filters which have been designed so the bottom of facility elevation is higher than the anticipated seasonal groundwater. ♦ Within Phase 1 there are eight (8) proposed vertical sand filters. Basins 1.1 and 1.2 are located within Common Lot 1C, Block 1, Basin 1.3 is located within Common Lot 1C, Block 6, Basin 1.8 is located within Common Lot 11C, Block 5, Basins 1.10 and 1.11 are located within Common Lot 1C, Block 3, and Basin 1.12 is located along the western boundary of the site easement within a future common lot. ♦ Within Phase 1 there are two (2) proposed bioretention swales that have been designed to provide a minimum of 3' between the bottom of facility elevations and the anticipated seasonal groundwater. Basin 1.4 is located in common Lot 1C, Block 1 and Basin 1.5 is located in common Lot 1C, Block 7. ♦ Phase 1 includes two(2)temporary stormwater retention ponds that have been designed to provide a minimum of 3' between the bottom of facility elevation and the anticipated seasonal groundwater. Basins 1.6 & 1.7 are located at the south end of N Dayspring Way within proposed temporary storm drain easements. Basins 1.6 and 1.7 have been sized for the 100-year event and will be removed and replaced with the development of Phase 2 of Dayspring Subdivision. SECTION 3 - Stormwater Equations Stormwater Conveyance (ACHD Policy Manual 8011.2) Q = iA where= Q = Discharge rate (ofs) C _ Coefficient of Runoff(dimensionless) i = Rainfall intensity (in/hr) for a duration equal to the time of concentration (Tc) over the contribuking area and for the design frequency. A = Site area (acres) Tc = Time of concentration Coefficient of Runoff(ACHD Policy Manual 8011.2.1) Estimated Runoff Coefficients for Various Surfaces Type of Surface Runoff Coefficients "C" Business Downtown areas 0.70-0.95 Urbannelghtwhoods 0.50-0.70 Residential Single Family 0.35.0.50 Multifamily 0.60.0.75 Residential1Fural) 0.25.0.40 ApartmentDwellingAreas 0.70 Industrial and Commerclal Light areas 0.80 Heavy areas 0.90 Parks,{emeterles 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20.0.40 UnlmpFaved areas 0.10.0.30 StFBBtS Asphalt 0.95 Gan{Fete 0.95 Brick 0.95 Roofs 0.95 Grant 0.75 Fields:Sandy sail Soll Type Slope A B { Flat 0.2% 0.04 0.07 0.11 0.1S Average,2.6% 0.09 0.12 0.15 0.20 Steep' % 0.13 0.18 0.23 0.26 Adapted from ASCE Design Storm Runoff Volume (ACHD Policy Manual 8011.3.2) V=CiA(3600) V: Design storm runoff volume required for storage C: Coefficient of Runoff is Rainfall Intensity per IDF Curve 1-hour 100-year storm event, i=0.96 1-hour 2-year storm event, i=0.26 A: Total catchment area(acres) Time of Concentration TC=TC-C,+TC-s TC : Total time of concentration LG Tc-c - 60 • VG Tc-G : Gutter time of concentration LG : Length of gutter flow VG : Gutter flow velocity VG=K„k Sr0.5 K„ : Empirical coefficient(3.281) k : Intercept coefficient(0.619) Sr : Slope (percent) 0.007(nL)0.8 TC-S - (p2)0.550.4 Tc-s : Overland time of concentration L : Length of overland(sheet) flow n : Manning's Roughness Coefficient(0.24) P2 : 2-year 24-hour rainfall(1.2 in.) S : Slope (ft/ft) Manning's Roughness Coefficient(ACHD Policy Manual 8011.5.3) Typical Range of Manning's Coefficient (n) for Channels and Pipes, Cpnd411; Matoridl Man:3ing's n' Closw conIJUItS Concrete pipe 0-010- 0.015 O M P 0-011 -0.037 Plastic (Smooth) 0.015 Plastic (cone aw) 0-018-0-025 PavamsnUgutter sections 0-012-0-016 rngi ll Open C han neK5 Concrete 0-011 -0.015 Rubble or riprap 0-020- 0.035 Vegetation 0.020-0.1 SO Base Soil 0-016 - 0.025 Rock Cut 0.025 - 0.045 Natural channels(minor streams, ROD mdth at flood stage <30 m(100 h)] Fairly regular sacs 0.025 - 0.050 Irr&gclar 9Ocbon with p6019 0 040 - 0.150 Lower values are usually For well-constructed and maintained{snnootherl pipes and channels Table 3-2. Manning's Roughness Coefficient(n)for Overland Sheet Flow,`' Surface Description n Smooth asphalt 0.011 Smooth concrete 0.012 Ordinary concrete lining 0.013 Good wood 0.014 Brick with cement mortar 0.014 Vitrified clay 01015 Cast iron 0.015 Corrugated metal pipe 0,024 Cement rubble surface M24 Fallow (no residue) 0.05 Cultivated soils Residue cover s 20% 0_06 Residue cover> 20°fo 0.17 Range(natural) 0_13 Grass Short grass prairie 0.15 Dens@ grasses 0.24 Bermuda grass 0.41 Woods' Light underbrush 0.40 Dense underbrush 4_$4 -When selecting n, consider cover to a height of about K mm. This is only part of the plant cover that will obstruct sheet Flow, SECTION 4 Primary Conveyance & Stormwater Facility Calculations BASIN CATCHMENT AREA 1.1 BASIN CHARACTERISTICS Basin Area: I 0.66 Acres Runoff Coefficient,C: 0.80 Rainfall Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr TIME OF CONCENTRATION Overland Flow Gutter Flow Sub-Catchment Length,L slope,s Tc-s Elev 1 Elev 2 Length,LG Slope,Sp Gutter Velocity,V. Tc-G Total Tc (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.1A 13.0 2.00 4.6 2539.2 2537.8 175 0.77 1.78 1.6 6.2 1.113 40.0 1.00 14.8 2539.0 2537.8 160 0.71 1.71 1.6 16.3 CONVEYANCE Sub-Catchment C Area,A i2 i25 i100 Q2 Q25 Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) MA 0.80 j.33 0.69 1.85 2.58 0.18 0.49 0.68 1.113 0.80 0.33 0.56 1.49 2.08 0.15 0.39 0.55 Total 0.66 0.33 0.88 1.23 SAND&GREASE TRAP No.of S&G Baffle Throat Vault Size Traps Spacing Width Throat Area Flow Rate, Q100 Throat Velocity, V Flow Rate Check Velocity Check (galon) (inch) (inch) (ft) (cfs) (fps) Q100<3.33 cfs V<0.5 fps 1000 1 20 48 6.67 1.23 0.18 TRUE TRUE STORAGE VOLUMES(Vertical Sand Filter) Chamber 1 Req'd Volume, V2-YR Ll W1 dl Pipe Volume,VPl Volume,VRl Storage Volume,Vl (ft) (ft) (ft) (ft) (ft3) (ft: ) (ft) 494 50 4.5 1 5 87 1 415 502 Chamber 2 Rock Void Design Infiltration Bed Infiltration Time to Drain Req'd Volume,V100-YR Lz W2 d2 Pipe Volume,VP2 Volume,VR2 Rate,I Volume,V21 Storage Volume,V2 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft') (hrs) 1,825 50 18 5 38 1,785 1.0 75 1,898 21.90 BASIN CATCHMENT AREA 1.2 BASIN CHARACTERISTICS Basin Area: I 0.46 Acres Runoff Coefficient,C: 0.75 Rainfall Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr TIME OF CONCENTRATION Overland Flow Gutter Flow Sub-Catchment Length,L Slope,s TC-s Elev 1 Elev 2 Length,LG Slope,Sp Gutter Velocity,V. Tc-G Total Tc (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.2 62.0 1.70 17.0 2538.5 1 2536.8 169 1 1.01 1 2.04 1.4 18.3 CONVEYANCE Sub-Catchment C Area,A i2 i25 iloo Q2 Q25 Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.2 0.75 0.49 0.52 1.39 1.94 0.19 0.51 0.71 Total 0.49 0.19 0.51 0.71 SAND&GREASE TRAP No.of S&G Baffle Throat Vault Size Traps Spacing Width Throat Area Flow Rate, Q100 Throat Velocity, V Flow Rate Check Velocity Check (galon) (inch) (inch) (ft) (cfs) (fps) Q100<3.33 cfs V<0.5 fps 1000 20 48 6.67 0.71 0.11 TRUE TRUE STORAGE VOLUMES(Vertical Sand Filter) Chamber 1 Req'd Volume, V2_YR Ll Wi dl Pipe Volume,VPl Volume,VR1 Storage Volume,Vl (ft') (ft) (ft) (ft) (ft3) (ft:) (ft') 323 4.5 1 4 78 1 293 371 Chamber 2 Rock Void Design Infiltration Bed Infiltration Time to Drain Req'd Volume,V100-YR Lz W2 d2 Pipe Volume,VP2 Volume,VR2 Rate,I Volume,V21 Storage Volume,V2 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft') (hrs) 1,192 45 4 35 1,210 1.0 64 1,308 16.83 BASIN CATCHMENT AREA 1.3 BASIN CHARACTERISTICS Basin Area: I 1.22 Acres Runoff Coefficient,C: 0.65 Rainfall Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr TIME OF CONCENTRATION Overland Flow Gutter Flow Sub-Catchment Length,L slope,s Tc-s Elev 1 Elev 2 Length,LG Slope,Sp Gutter Velocity,V. Tc� Total Tc (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.3A 14.5 2.00 5.0 2539.5 2538.1 210 0.65 1.63 2.1 7.1 1.313 13.0 1.50 5.1 2539.2 2538.1 215 0.50 1.44 2.5 7.6 CONVEYANCE Sub-Catchment C Area,A i2 i25 i100 Q2 Q25 Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.3A 0.60 j.94 0.69 1.85 2.58 0.39 1.04 1.46 1.313 0.80 0.28 0.69 1.85 2.58 0.15 0.41 0.58 Total 1.22 0.54 1.46 2.03 SAND&GREASE TRAP No.of S&G Baffle Throat Vault Size Traps Spacing Width Throat Area Flow Rate, Q100 Throat Velocity, V Flow Rate Check Velocity Check (galon) (inch) (inch) (ft) (cfs) (fps) Q100<3.33 cfs V<0.5 fps 1000 1 20 48 6.67 2.03 0.30 TRUE TRUE STORAGE VOLUMES(Vertical Sand Filter) Chamber 1 Req'd Volume, V2-YR Ll W1 dl Pipe Volume,VPl Volume,VRl Storage Volume,Vl (ft) (ft) (ft) (ft) (ft3) (ft: ) (ft) 738 80 4 1 5.5 140 1 648 788 Chamber 2 Rock Void Design Infiltration Bed Infiltration Time to Drain Req'd Volume,V100-YR Lz W2 d2 Pipe Volume,VP2 Volume,VR2 Rate,I Volume,V21 Storage Volume,V2 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft') (hrs) 2,723 80 15 5.5 62 2,615 1.0 100 2,777 24.51 BASIN CATCHMENT AREA 1.4 BASIN CHARACTERISTICS Basin Area,A: 0.05 ac Runoff Coefficient,C: 0.8 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES 100-Year Event(Roadside Swale Volume) Bed Design Infiltration Bottom Pond Infiltration Volume, Time to Req'd Volume, V100-YR Top Area Depth Area Volume Rate,I V21 Drain 90% (ft3) (ft) (ft) (ft) I (ft) (in/hr) (ft') I (hrs) 138 204 0.58 68 1 79 1.0 6 22.0 Gravel Storage Gravel Volume, Req'd Volume, V100-YR Ll W dl VR1 Req.Vol-Pond Vol.(ft3) (ft) (ft) (ft) (ft) 59 34 2 2.5 68 Total Volume Provided (ft3) 147 TIME OF CONCENTRATION Overland Flow Gutter Flow Gutter Slope, Velocity, Sub-Catchment Length,L s TC-s Elev 1 Elev 2 Length,Lc Slope,Sp VG Tc-G Total Tc (ft) M (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.4 32 1.50 10.5 2538.3 2538.1 32 0.50 1.44 0.4 10.9 CONVEYANCE Sub-Catchment C Area,A iz i2s oo Qz Q2S Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.4 0.80 1 0.05 1 0.67 1.8 2.51 0.03 0.07 0.10 BASIN CATCHMENT AREA 1.5 BASIN CHARACTERISTICS Basin Area,A: 0.05 ac Runoff Coefficient,C: 0.8 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES 100-Year Event(Roadside Swale Volume) Bed Design Infiltratio Bottom Pond Infiltratio n Volume, Time to Req'd Volume, VIOOvR Top Area Depth Area Volume n Rate,I V21 Drain 90% (ft3) (ft) (ft) (ft') (ft') (in/hr) (ft') (hrs) 138 176 0.58 58 68 1.0 5 25.7 Gravel Storage Gravel Volume, Req'd Volume, V100-YR Ll W d1 VRl Req.Vol-Pond Vol.(ft) (ft) (ft) (ft) (ft) 70 29 2 3.25 75 Total Volume Provided (ft') 143 TIME OF CONCENTRATION Overland Flow Gutter Flow Gutter Slope, Velocity, Sub-Catchment Length,L s Tc-s Elev 1 Elev 2 Length,LG Slope,Sp VG Tc-G Total Tc (ft) M (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.5 32 1.50 10.5 2538.3 2538.1 32 0.50 1.44 0.4 10.9 CONVEYANCE Sub-Catchment C Area,A i2 i25 i100 42 Q2S Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.5 0.80 0.05 1 0.67 1.8 2.51 0.03 1 0.07 0.10 TEMP. BASIN CATCHMENT AREA 1.6 BASIN CHARACTERISTICS Basin Area: I 0.10 Acres Runoff Coefficient,C: 1 0.50 Rainfall Intensity,is I 0.96 in/hr STORAGE VOLUMES Temporary Basin Req'd Volume Botom V100YR Depth Area Top Area Basin Volume (ft') (ft) (ft') (ft') (ft') 173 1.0 102.00 314.0 208.0 TEMP BASIN CATCHMENT AREA 1.7 BASIN CHARACTERISTICS Basin Area: I 0.18 Acres Runoff Coefficient,C: 1 0.50 Rainfall Intensity,is I 0.96 in/hr STORAGE VOLUMES Temporary Basin Req'd Volume Botom V100YR Depth Area Top Area Basin Volume (ft') (ft) (ft') (ft') (ft') 311 1.0 223.00 558.0 390.5 BASIN CATCHMENT AREA 1.8 BASIN CHARACTERISTICS Basin Area: I 1.15 Acres Runoff Coefficient,C: 0.64 Rainfall Intensity,is 1 0.96 in/hr Infiltration Rate,r: I 1.0 in/hr TIME OF CONCENTRATION Overland Flow Gutter Flow Sub-Catchment Length,L Slope,s Tc-s Elev 1 Elev 2 Length,L� Slope,Sp Gutter Velocity,V� Tc-G Total Tc (ft) M (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.8A 67.5 1.00 22.5 2539.6 2537.5 267 0.81 1.83 2.4 24.9 1.813 46.0 1.50 14.0 2539.0 2537.5 242 0.62 1.59 2.5 16.6 1.8C 27.0 1.00 10.8 2537.9 2537.4 25 1.88 2.78 0.1 10.9 1.81) 27.0 1.00 10.8 2537.8 2537.4 25 1.56 2.54 0.2 11.0 1.8E 17.5 2.00 5.8 2539.1 2538.2 96 0.90 1.92 0.8 6.6 1.81' 17.5 2.00 5.8 2539.1 2538.2 96 0.90 1.92 0.8 6.6 CONVEYANCE Sub-Catchment C Area,A i2 i25 60 Q2 Q25 Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.8A 0.50 0.75 0.43 1.14 1.58 0.16 0.43 0.59 1.8B 0.90 0.18 0.56 1.48 2.06 0.09 0.24 0.33 1.8C 0.90 0.02 0.67 1.8 2.51 0.01 0.03 0.05 1.81) 0.90 0.02 0.67 1.79 2.50 0.01 0.03 0.05 1.8E 0.90 0.09 0.69 1.85 2.58 0.06 0.15 0.21 1.8F 0.90 0.09 0.69 1.85 2.58 0.06 0.15 0.21 Total 0.64 1.15 0.39 1.03 1.43 SAND&GREASE TRAP No.of S&G Throat Vault Size Traps Baffle Spacing Width Throat Area Flow Rate, Qloo Throat Velocity, V Flow Rate Check Velocity Check (galon) (inch) (inch) (ft 2) (cfs) (fps) Qlw<3.33 cfs V<0.5 fps 1000 1 20 48 6.67 1.43 0.22 TRUE TRUE STORAGE VOLUMES(Vertical Sand Filter) Chamber 1 Req'd Volume, V2-YR LI WI d1 Pipe Volume,VPI Volume,VRI Storage Volume,VI (ft) (ft) (ft) (ft) (ft') (ft') (ft') 688 62 4.5 6 108 627 734 Chamber 2 Rock Void Design Infiltration Bed Infiltration Time to Drain Req'd Volume,VI00-YR L2 W2 d2 Pipe Volume,VP2 Volume,VR2 Rate,I Volume,V21 Storage Volume,V2 90% (ft) (ft) (ft) (ft) (ft') (ft) (in/hr) (ft') (ft') (hrs) 2,540 62 17.5 6 48 2,585 1.0 90 2,723 25.28 BASIN CATCHMENT AREA 1.9 BASIN CHARACTERISTICS Basin Area: I 1.31 Acres Runoff Coefficient,C: 0.70 Rainfall Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr TIME OF CONCENTRATION Overland Flow Gutter Flow Sub-Catchment Length,L slope,s TC-s Elev 1 Elev 2 Length,LG Slope,Sp Gutter Velocity,V. Tc-G Total Tc (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.9A 16.0 2.00 5.4 2539.5 2537.3 323 0.67 1.66 3.2 8.6 1.913 16.0 2.00 5.4 2538.1 2537.3 152 0.50 1.44 1.8 7.1 CONVEYANCE Sub-Catchment C Area,A i2 i25 i100 Q2 Q25 Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.9A 0.70 1.04 0.69 1.85 2.58 0.50 1.35 1.88 1.913 0.70 0.27 0.69 1.85 2.58 0.13 0.35 0.49 Total 1.31 0.63 1.70 2.37 SAND&GREASE TRAP No.of S&G Baffle Throat Vault Size Traps Spacing Width Throat Area Flow Rate, Q100 Throat Velocity, V Flow Rate Check Velocity Check (galon) (inch) (inch) (ft) (cfs) (fps) Q100<3.33 cfs V<0.5 fps 1000 1 20 48 6.67 2.37 0.35 TRUE TRUE STORAGE VOLUMES(Vertical Sand Filter) Chamber 1 Req'd Volume, V2-YR Ll W1 dl Pipe Volume,VPl Volume,VRl Storage Volume,Vl (ft) (ft) (ft) (ft) (ft3) (ft: ) (ft) 858 80 6.5 1 4 140 1 776 916 Chamber 2 Rock Void Design Infiltration Bed Infiltration Time to Drain Req'd Volume,V100-YR Lz W2 d2 Pipe Volume,VP2 Volume,VR2 Rate,I Volume,V21 Storage Volume,V2 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft') (hrs) 3,169 80 4 62 3,047 1.0 160 3,269 17.83 BASIN CATCHMENT AREA 1.10 BASIN CHARACTERISTICS Basin Area: I 2.50 Acres Runoff Coefficient,C: 0.50 Rainfall Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr TIME OF CONCENTRATION Overland Flow Gutter Flow Sub-Catchment Length,L slope,s Tc-s Elev 1 Elev 2 Length,LG Slope,Sp Gutter Velocity,V. Tc� Total Tc (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.10A 70.0 1.00 23.1 2537.8 2536.3 230 0.65 1.63 2.3 25.5 1.10E 70.0 1.00 23.1 2539.6 2536.3 542 0.62 1.60 5.6 28.7 CONVEYANCE Sub-Catchment C Area,A i2 i25 i100 Q2 Q25 Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.10A 0.so 1.10 0.43 1.13 1.56 0.24 0.62 0.86 1.10E 0.50 1.40 0.42 1.1 1.53 0.29 0.77 1.07 Tota 1 2.50 0.53 1.39 1.93 SAND&GREASE TRAP No.of S&G Baffle Throat Vault Size Traps Spacing Width Throat Area Flow Rate, Q100 Throat Velocity, V Flow Rate Check Velocity Check (galon) (inch) (inch) (ft) (cfs) (fps) Q100<3.33 cfs V<0.5 fps 1000 1 20 48 6.67 1.93 0.29 TRUE TRUE STORAGE VOLUMES(Vertical Sand Filter) Chamber 1 Req'd Volume, V2-YR Ll W1 dl Pipe Volume,VPl Volume,VRl Storage Volume,Vl (ft) (ft) (ft) (ft) (ft3) (ft: ) (ft) 1,170 85 8.5 1 4 148 1 1,097 1,245 Chamber 2 Rock Void Design Infiltration Bed Infiltration Time to Drain Req'd Volume,V100-YR Lz W2 d2 Pipe Volume,VP2 Volume,VR2 Rate,I Volume,V21 Storage Volume,V2 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft') (hrs) 4,320 85 4 66 4,326 1.0 227 4,618 17.15 BASIN CATCHMENT AREA 1.11 BASIN CHARACTERISTICS Basin Area: 2.33 Acres Runoff Coefficient,C: 0.72 Rainfall Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr TIME OF CONCENTRATION Overland Flow Gutter Flow Sub-Catchment Length,L Slope,s TC-s Elev 1 Elev 2 Length,L, Slope,Sp Gutter Velocity,V. Tc-G Total Tc (ft) M (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.11A 56.0 1.00 19.3 2538.1 2536.3 345 0.53 1.48 3.9 23.2 1.1113 39.0 1.00 14.5 2538.2 2536.3 325 0.61 1.58 3.4 17.9 1.11C 35.0 1.00 13.3 2539.1 2538.7 96 0.47 1.39 1.2 14.4 1.11D 35.0 1.00 13.3 2539.1 2538.7 96 0.47 1.39 1.2 14.4 1.11E 25.0 1.00 10.1 2538.3 2537.8 26 1.73 2.67 0.2 10.3 1.11F 35.0 1.00 13.3 2538.6 2537.8 57 1.39 2.39 0.4 13.7 CONVEYANCE Sub-Catchment C Area,A i2 i25 Q2 Q25 Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.11A 0.70 1.44 0.45 1.20 1.66 0.45 1.21 1.67 1.11B 0.70 0.67 0.53 1.41 1.97 0.25 0.66 0.92 1.11C 0.90 0.08 0.60 1.59 2.22 0.04 0.11 0.16 1.11D 0.90 0.08 0.60 1.59 2.22 0.04 0.11 0.16 1.11E 0.90 0.02 0.69 1.85 2.58 0.01 0.03 0.05 1.11F 0.90 0.04 0.62 1.65 2.30 0.02 0.06 0.08 Total 0.72 2.33 0.82 2.19 705 SAND&GREASE TRAP No.of S&G Baffle Throat Vault Size Traps Spacing Width Throat Area Flow Rate, Q,,, Throat Velocity, V Flow Rate Check Velocity Check (galon) (inch) (inch) (ft') (cfs) (fps) Q100<3.33cfs V<0.5fps 20 48 6.67 3.05 0.46 TRUE TRUE STORAGE VOLUMES(Vertical Sand Filter) Chamber 1 Req'd Volume, Vz_YR L, W, d, Pipe Volume,Val Volume,VR1 Storage Volume,Vl (ft') (ft) I (ft) (ft) (ft') (ft') (ft) 1,568 100 9.5 4 175 1,450 1,625 Chamber 2 Rock Void Design Infiltration Bed Infiltration Time to Drain Req'd Volume,V100-111 L2 Wz dz Pipe Volume,V12 Volume,VR2 Rate,I Volume,V21 Storage Volume,Vz 90% (ft') (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft') (hrs) 5,789 100 35 4 78 5,569 1.0 292 5,938 17.86 BASIN CATCHMENT AREA 1.12 BASIN CHARACTERISTICS Basin Area: I 0.42 Acres Runoff Coefficient,C: 0.81 Rainfall Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr TIME OF CONCENTRATION Overland Flow Gutter Flow Sub-Catchment Length,L slope,s Tc-s Elev 1 Elev 2 Length,LG Slope,Sp Gutter Velocity,V. Tc-G Total Tc (min.) (ft) (ft) (ft) M (ft/sec) (min.) (min.) 1.12A 25.0 1.00 10.1 2538.0 2536.8 220 0.55 1.51 2.4 12.6 1.12E 25.0 1.00 10.1 2538.2 2536.8 220 0.64 1.63 2.3 12.4 CONVEYANCE Sub-Catchment C Area,A i2 i25 i100 Q2 Q25 Q100 (acres) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) 1.12A 0.75 j.24 0.64 1.71 2.38 0.12 0.31 0.43 1.12B 0.90 0.18 0.64 1.71 2.38 0.10 0.28 0.39 Total 0.42 0.22 0.58 0.81 SAND&GREASE TRAP No.of S&G Baffle Throat Vault Size Traps Spacing Width Throat Area Flow Rate, Q100 Throat Velocity, V Flow Rate Check Velocity Check (galon) (inch) (inch) (ft) (cfs) (fps) Q100<3.33 cfs V<0.5 fps 1000 1 20 48 6.67 0.81 0.12 TRUE TRUE STORAGE VOLUMES(Vertical Sand Filter) Chamber 1 Req'd Volume, V2-YR Ll W1 dl Pipe Volume,VPl Volume,VRl Storage Volume,Vl (ft) (ft) (ft) (ft) (ft3) (ft: ) (ft) 320 50 4 1 4.5 87 1 325 412 Chamber 2 Rock Void Design Infiltration Bed Infiltration Time to Drain Req'd Volume,V100-YR Lz W2 d2 Pipe Volume,VP2 Volume,VR2 Rate,I Volume,V21 Storage Volume,V2 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft') (hrs) 1,182 s0 4.5 38 1,245 1.0 58 1,341 18.24 SECTION 5 Intensity-Duration-Frequency Curve ACHD Intensity-Duration-Frequency Intensity(inches per hour) Design Storm 2 5 10 25 50 100 Tc(hr) Tc(min) 0.17 10 0.69 1.15 1.48 1.85 2.20 2.58 0.25 15 0.59 0.97 1.22 1.56 1.86 2.18 0.33 20 0.49 0.81 1.01 1.30 1.54 1.81 0.42 25 0.43 0.71 0.89 1.14 1.35 1.58 0.50 30 0.41 0.67 0.85 1.08 1.29 1.51 0.58 35 0.34 0.56 0.70 0.90 1.07 1.25 0.67 40 0.31 0.51 0.64 0.82 0.98 1.15 0.75 45 0.29 0.48 0.60 0.77 0.91 1.07 0.83 50 0.27 0.45 0.56 0.72 0.85 1.00 0.92 55 0.26 0.43 0.54 0.69 0.82 0.96 1 60 0.26 0.43 0.54 0.69 0.82 0.96 2 120 0.16 0.25 0.31 0.39 0.46 0.54 3 180 0.13 0.19 0.23 0.29 0.34 0.40 6 360 0.09 0.12 0.14 0.18 0.21 0.25 12 720 0.06 0.08 0.10 0.12 0.14 0.16 24 1440 0.04 0.06 0.06 0.08 0.09 0.10 Intensity Duration Frequency - 2 3 - -5 -x-10 2.5 -�25 50 2 f 100 L s a v 1.5 c 41 41 �x � 1 c \X�X --x__ 0.5 _ \X�x�x_X-x-x -------------------------- X 0 10 15 20 25 30 35 40 45 50 55 60 120 180 360 720 1440 Duration (minutes) SECTION 6 Pipe Flow Calculations Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 23 2025 100-YR TO SDCB 1.1 B TO SDMH 1.1 C Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.28 Q (cfs) = 0.550 Area (sqft) = 0.18 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.02 Slope (%) = 0.50 Wetted Perim (ft) = 1.12 N-Value = 0.010 Crit Depth, Yc (ft) = 0.31 Top Width (ft) = 0.90 Calculations EGL (ft) = 0.42 Compute by: Known Q Known Q (cfs) = 0.55 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 23 2025 100-YR TO SDCB 1.1A SDMH 1.1C Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.21 Q (cfs) = 0.680 Area (sqft) = 0.12 Invert Elev (ft) = 100.00 Velocity (ft/s) = 5.63 Slope (%) = 2.38 Wetted Perim (ft) = 0.95 N-Value = 0.010 Crit Depth, Yc (ft) = 0.35 Top Width (ft) = 0.82 Calculations EGL (ft) = 0.70 Compute by: Known Q Known Q (cfs) = 0.68 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 Noor 100.00 0.00 99.50 —0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 23 2025 100-YR SDMH 1.1 C TO SDMH 1.1 B Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.43 Q (cfs) = 1.230 Area (sqft) = 0.33 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.78 Slope (%) = 0.50 Wetted Perim (ft) = 1.43 N-Value = 0.010 Crit Depth, Yc (ft) = 0.47 Top Width (ft) = 0.99 Calculations EGL (ft) = 0.65 Compute by: Known Q Known Q (cfs) = 1.23 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday,Dec 15 2025 100 YR - SDCB 1.2 TO SDMH 1.2 Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.32 Q (cfs) = 0.710 Area (sqft) = 0.22 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.26 Slope (%) = 0.50 Wetted Perim (ft) = 1.20 N-Value = 0.010 Crit Depth, Yc (ft) = 0.35 Top Width (ft) = 0.93 Calculations EGL (ft) = 0.49 Compute by: Known Q Known Q (cfs) = 0.71 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDCB 1.3B TO SDCB 1.3A Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.29 Q (cfs) = 0.580 Area (sqft) = 0.19 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.05 Slope (%) = 0.50 Wetted Perim (ft) = 1.14 N-Value = 0.010 Crit Depth, Yc (ft) = 0.32 Top Width (ft) = 0.91 Calculations EGL (ft) = 0.43 Compute by: Known Q Known Q (cfs) = 0.58 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday,Dec 15 2025 100 YR - SDCB UA TO S&G TRAP 1.3 Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.57 Q (cfs) = 2.030 Area (sqft) = 0.46 Invert Elev (ft) = 100.00 Velocity (ft/s) = 4.37 Slope (%) = 0.50 Wetted Perim (ft) = 1.71 N-Value = 0.010 Crit Depth, Yc (ft) = 0.61 Top Width (ft) = 0.99 Calculations EGL (ft) = 0.87 Compute by: Known Q Known Q (cfs) = 2.03 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 - 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.8A TO SDMH 1.8A Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.24 Q (cfs) = 0.930 Area (sqft) = 0.15 Invert Elev (ft) = 100.00 Velocity (ft/s) = 6.40 Slope (%) = 2.81 Wetted Perim (ft) = 1.02 N-Value = 0.010 Crit Depth, Yc (ft) = 0.41 Top Width (ft) = 0.85 Calculations EGL (ft) = 0.88 Compute by: Known Q Known Q (cfs) = 0.93 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.8B TO SDCB 1.8A Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.22 Q (cfs) = 0.330 Area (sqft) = 0.13 Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.55 Slope (%) = 0.50 Wetted Perim (ft) = 0.98 N-Value = 0.010 Crit Depth, Yc (ft) = 0.24 Top Width (ft) = 0.83 Calculations EGL (ft) = 0.32 Compute by: Known Q Known Q (cfs) = 0.33 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.8C TO SDMH 1.8C Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.07 Q (cfs) = 0.050 Area (sqft) = 0.02 Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.02 Slope (%) = 2.29 Wetted Perim (ft) = 0.54 N-Value = 0.010 Crit Depth, Yc (ft) = 0.10 Top Width (ft) = 0.51 Calculations EGL (ft) = 0.13 Compute by: Known Q Known Q (cfs) = 0.05 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.8D TO SDMH 1.8C Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.09 Q (cfs) = 0.050 Area (sqft) = 0.04 Invert Elev (ft) = 100.00 Velocity (ft/s) = 1.42 Slope (%) = 0.50 Wetted Perim (ft) = 0.61 N-Value = 0.010 Crit Depth, Yc (ft) = 0.10 Top Width (ft) = 0.57 Calculations EGL (ft) = 0.12 Compute by: Known Q Known Q (cfs) = 0.05 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.8E TO SDMH 1.8D Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.13 Q (cfs) = 0.210 Area (sqft) = 0.06 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.47 Slope (%) = 1.65 Wetted Perim (ft) = 0.74 N-Value = 0.010 Crit Depth, Yc (ft) = 0.19 Top Width (ft) = 0.67 Calculations EGL (ft) = 0.32 Compute by: Known Q Known Q (cfs) = 0.21 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.8F TO SDMH 1.8D Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.18 Q (cfs) = 0.210 Area (sqft) = 0.10 Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.16 Slope (%) = 0.50 Wetted Perim (ft) = 0.88 N-Value = 0.010 Crit Depth, Yc (ft) = 0.19 Top Width (ft) = 0.77 Calculations EGL (ft) = 0.25 Compute by: Known Q Known Q (cfs) = 0.21 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDMH 1.8A TO S&G TRAP 1.8 Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.47 Q (cfs) = 1.430 Area (sqft) = 0.36 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.92 Slope (%) = 0.50 Wetted Perim (ft) = 1.51 N-Value = 0.010 Crit Depth, Yc (ft) = 0.51 Top Width (ft) = 1.00 Calculations EGL (ft) = 0.71 Compute by: Known Q Known Q (cfs) = 1.43 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDMH 1.8B TO SDMH 1.8A Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.27 Q (cfs) = 0.510 Area (sqft) = 0.17 Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.97 Slope (%) = 0.50 Wetted Perim (ft) = 1.09 N-Value = 0.010 Crit Depth, Yc (ft) = 0.30 Top Width (ft) = 0.89 Calculations EGL (ft) = 0.41 Compute by: Known Q Known Q (cfs) = 0.51 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDMH 1.8C TO SDMH 1.8B Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.12 Q (cfs) = 0.100 Area (sqft) = 0.05 Invert Elev (ft) = 100.00 Velocity (ft/s) = 1.85 Slope (%) = 0.50 Wetted Perim (ft) = 0.71 N-Value = 0.010 Crit Depth, Yc (ft) = 0.13 Top Width (ft) = 0.65 Calculations EGL (ft) = 0.17 Compute by: Known Q Known Q (cfs) = 0.10 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDMH 1.8D TO SDMH 1.8B Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.17 Q (cfs) = 0.420 Area (sqft) = 0.09 Invert Elev (ft) = 100.00 Velocity (ft/s) = 4.74 Slope (%) = 2.36 Wetted Perim (ft) = 0.85 N-Value = 0.010 Crit Depth, Yc (ft) = 0.27 Top Width (ft) = 0.75 Calculations EGL (ft) = 0.52 Compute by: Known Q Known Q (cfs) = 0.42 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR - SDCB1.9A TO SDMH 1.9C Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.51 Q (cfs) = 1.880 Area (sqft) = 0.40 Invert Elev (ft) = 100.00 Velocity (ft/s) = 4.64 Slope (%) = 0.63 Wetted Perim (ft) = 1.59 N-Value = 0.010 Crit Depth, Yc (ft) = 0.59 Top Width (ft) = 1.00 Calculations EGL (ft) = 0.85 Compute by: Known Q Known Q (cfs) = 1.88 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 Noor 100.50 _ 0.50 100.00 0.00 99.50 —0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday,Dec 15 2025 100 YR - SDCB1.9B TO SDMH 1.9C Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.26 Q (cfs) = 0.490 Area (sqft) = 0.16 Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.99 Slope (%) = 0.50 Wetted Perim (ft) = 1.07 N-Value = 0.010 Crit Depth, Yc (ft) = 0.29 Top Width (ft) = 0.88 Calculations EGL (ft) = 0.40 Compute by: Known Q Known Q (cfs) = 0.49 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR - SDMH 1.9C TO SDMH 1.9B Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.64 Q (cfs) = 2.370 Area (sqft) = 0.53 Invert Elev (ft) = 100.00 Velocity (ft/s) = 4.46 Slope (%) = 0.50 Wetted Perim (ft) = 1.85 N-Value = 0.010 Crit Depth, Yc (ft) = 0.66 Top Width (ft) = 0.96 Calculations EGL (ft) = 0.95 Compute by: Known Q Known Q (cfs) = 2.37 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday,Dec 15 2025 100 YR - SDCB 1.10B TO SDCB 1.10A Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.40 Q (cfs) = 1.070 Area (sqft) = 0.29 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.64 Slope (%) = 0.50 Wetted Perim (ft) = 1.37 N-Value = 0.010 Crit Depth, Yc (ft) = 0.44 Top Width (ft) = 0.98 Calculations EGL (ft) = 0.61 Compute by: Known Q Known Q (cfs) = 1.07 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday,Dec 15 2025 100 YR - SDCB 1.10A TO SDMH 1.10 Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.56 Q (cfs) = 1.930 Area (sqft) = 0.45 Invert Elev (ft) = 100.00 Velocity (ft/s) = 4.25 Slope (%) = 0.50 Wetted Perim (ft) = 1.69 N-Value = 0.010 Crit Depth, Yc (ft) = 0.60 Top Width (ft) = 0.99 Calculations EGL (ft) = 0.84 Compute by: Known Q Known Q (cfs) = 1.93 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDCB 1.11A TO SDMH 1.11A Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.77 Q (cfs) = 3.050 Area (sqft) = 0.65 Invert Elev (ft) = 100.00 Velocity (ft/s) = 4.69 Slope (%) = 0.50 Wetted Perim (ft) = 2.15 N-Value = 0.010 Crit Depth, Yc (ft) = 0.75 Top Width (ft) = 0.84 Calculations EGL (ft) = 1.11 Compute by: Known Q Known Q (cfs) = 3.05 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.11 B TO SDMH 1.11 B Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.37 Q (cfs) = 0.920 Area (sqft) = 0.27 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.47 Slope (%) = 0.50 Wetted Perim (ft) = 1.31 N-Value = 0.010 Crit Depth, Yc (ft) = 0.41 Top Width (ft) = 0.97 Calculations EGL (ft) = 0.56 Compute by: Known Q Known Q (cfs) = 0.92 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.11 C TO SDMH 1.11 D Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.11 Q (cfs) = 0.160 Area (sqft) = 0.05 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.35 Slope (%) = 1.93 Wetted Perim (ft) = 0.68 N-Value = 0.010 Crit Depth, Yc (ft) = 0.17 Top Width (ft) = 0.63 Calculations EGL (ft) = 0.28 Compute by: Known Q Known Q (cfs) = 0.16 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDCB 1.11 D TO SDMH 1.11 D Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.15 Q (cfs) = 0.160 Area (sqft) = 0.08 Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.13 Slope (%) = 0.50 Wetted Perim (ft) = 0.80 N-Value = 0.010 Crit Depth, Yc (ft) = 0.17 Top Width (ft) = 0.72 Calculations EGL (ft) = 0.22 Compute by: Known Q Known Q (cfs) = 0.16 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDCB 1.11 E TO SDMH 1.11 E Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.07 Q (cfs) = 0.050 Area (sqft) = 0.02 Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.02 Slope (%) = 2.29 Wetted Perim (ft) = 0.54 N-Value = 0.010 Crit Depth, Yc (ft) = 0.10 Top Width (ft) = 0.51 Calculations EGL (ft) = 0.13 Compute by: Known Q Known Q (cfs) = 0.05 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDCB 1.11 F TO SDMH 1.11 E Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.11 Q (cfs) = 0.080 Area (sqft) = 0.05 Invert Elev (ft) = 100.00 Velocity (ft/s) = 1.67 Slope (%) = 0.50 Wetted Perim (ft) = 0.68 N-Value = 0.010 Crit Depth, Yc (ft) = 0.12 Top Width (ft) = 0.63 Calculations EGL (ft) = 0.15 Compute by: Known Q Known Q (cfs) = 0.08 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDMH 1.11 B TO SDCB 1.11A Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.45 Q (cfs) = 1.370 Area (sqft) = 0.34 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.97 Slope (%) = 0.50 Wetted Perim (ft) = 1.47 N-Value = 0.010 Crit Depth, Yc (ft) = 0.50 Top Width (ft) = 1.00 Calculations EGL (ft) = 0.70 Compute by: Known Q Known Q (cfs) = 1.37 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDMH 1.11 C TO SDMH 1.11 B Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.21 Q (cfs) = 0.450 Area (sqft) = 0.12 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.72 Slope (%) = 1.00 Wetted Perim (ft) = 0.95 N-Value = 0.010 Crit Depth, Yc (ft) = 0.28 Top Width (ft) = 0.82 Calculations EGL (ft) = 0.43 Compute by: Known Q Known Q (cfs) = 0.45 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 Noor 100.00 0.00 99.50 —0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Dec 16 2025 100 YR SDMH 1.11 D TO SDMH 1.11 C Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.17 Q (cfs) = 0.320 Area (sqft) = 0.09 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.61 Slope (%) = 1.35 Wetted Perim (ft) = 0.85 N-Value = 0.010 Crit Depth, Yc (ft) = 0.24 Top Width (ft) = 0.75 Calculations EGL (ft) = 0.37 Compute by: Known Q Known Q (cfs) = 0.32 Elev (ft) Section Depth (ft 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 v 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDMH 1.11 E TO SDMH 1.11 C Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.14 Q (cfs) = 0.130 Area (sqft) = 0.07 Invert Elev (ft) = 100.00 Velocity (ft/s) = 1.92 Slope (%) = 0.50 Wetted Perim (ft) = 0.77 N-Value = 0.010 Crit Depth, Yc (ft) = 0.15 Top Width (ft) = 0.70 Calculations EGL (ft) = 0.20 Compute by: Known Q Known Q (cfs) = 0.13 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDCB 1.12B TO SDCB 1.12A Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.24 Q (cfs) = 0.390 Area (sqft) = 0.15 Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.68 Slope (%) = 0.50 Wetted Perim (ft) = 1.02 N-Value = 0.010 Crit Depth, Yc (ft) = 0.26 Top Width (ft) = 0.85 Calculations EGL (ft) = 0.35 Compute by: Known Q Known Q (cfs) = 0.39 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Saturday, Dec 20 2025 100 YR - SDCB 1.12A TO SDMH 1.12 Circular Highlighted Diameter (ft) = 1.00 Depth (ft) = 0.34 Q (cfs) = 0.810 Area (sqft) = 0.24 Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.41 Slope (%) = 0.50 Wetted Perim (ft) = 1.25 N-Value = 0.010 Crit Depth, Yc (ft) = 0.38 Top Width (ft) = 0.95 Calculations EGL (ft) = 0.52 Compute by: Known Q Known Q (cfs) = 0.81 Elev (ft) Section Depth (ft) 102.00 2.00 101.50 1.50 101.00 1.00 100.50 0.50 100.00 0.00 99.50 -0.50 0 1 2 3 Reach (ft) SECTION 7 Drainage Basin Map W W WUSTICK RD + LEGENDI 1C - - BASIN BOUNDARY LINE BAS 1. \ � ¢ l SUB-BASIN BOUNDARY LINE 8 9 10 11 0. ac. 1 12 13 BASIN 1.113 BASIN 1.1A I I I 1 0.33 ac. 0.33 ac. BLO 01 BASIN 1.1 BASIN AREA INFO 6.92 ac. `� I -- -- -- -- -- -- -- -- - -- I BASIN 1.1B SUB-BASIN AREA INFO 5.17 ac. BLOCK 02 \ m I I I I I a \ TIME OF CONCENTRATION I 7 6 I 5 1 1 4 3 2 I \ BASIN 1.11E BASIN 1.11E BASIN 1.8C BASIN 1.81) c ®-If ROADWAY INLET 0.02ac. 0.04ac. 0.02ac. 0.02ac. 1C I I c�'-�\ �� • BASIN 1.12B BASIN 1.11D BASIN I \ L \ 0.18 ac. BASIN 1.12 0.08ac. 0.09 ac. BASIN1.86 B-ASIN 1� I� 0�, \ 0.42 ac. \ O� BASIN 1.11C BASIN 1.8E 0.24 ac.. 0.18 ac. W MCMURTREY ST BASIN 1._ 0.08 ac. 0.09 ac. .46 ac. \ m II z 13 12 BASIN 1.8 10 \ J II I o 10 BASIN 1.11 BASIN 1.10 1.15 ac. \ BASIN 1.8A \ 2.33 ac.- - - - 2.51 ac. 9 0.75ac. 9 r a FUTURE PHASE C - - - - - $ a 8 \ $ - - - - - - BASIN 1.3A BASIN 1.3B \ _ w 7 0.94a� 0.28 ac. ° \ 7 iQ \ BASIN 1.11E I BASIN 1.11 I BL CK 3 I w 0.67 ac. I 1.44 ac. BASIN 1.10B 6 6 I o 1.40 ac. 1 2 3 1 4 5 6 7 8 9 10 11 5 5 BLOCK 05 BLOCK 06 BASIN 1. II ALLEY C(PUBLIC) 4 4 1.22 ac. a 3 w 2 3 4 5 6 7 8 9 10 11 1 ;: I 2 BASIN 1.4 B OCK 04 2 0.05 ac. \ BASIN 0.27 ac. 1C BASIN 1.5 - 0.05 ac. ALLEY E Pueuc) TEMP. W BOWMILLS DR ASIN 1.7 1Cc� TEMP. 0.18 C. BASIN 1.6 N Q BASIN 1.9A 1C 0.10 ac. 1.04 ac. 1 1 BASIN 1.9 ' FEET I I 1.31 ac. 100 0 50 100 I I I GRAPHIC SCALE FUTURE PHASE FUTURE PHASE I I 1 inch=100 ft.Horizontal CESCE 00H,%UL4La14Z DAYSPRING SUBDIVISION NO. 1 Toll Broth.Achrs ENGINEERING PLANNING SURVEYING ENVIRONMENTAL DRAINAGE CATCHMENT PLAN ESE Consultants,Inc. 3103 W.Sheryl Drive•Suite 100•Mendian,ID 83642 January 8, 2026 - Meridian, Idaho AMERICA'S LUXURY HOME BUILDER* T:208-424-0020